In thermal transfer printing, the ribbon is contacted by a thermal print head to produce local heating of an area of the ribbon upon thermal activation of a thermal element of the thermal print head. Thus heat is selectively applied to portions of the ribbon to melt an ink layer contiguous to the element via a support element onto the paper being printed upon. Ink is transferred from the ribbon to the paper at the localized areas in which heat is generated.
The prior thermal transfer printing ribbon comprises a support member coated with meltable ink which includes a colorant and a binder which is made of wax primarily. Satisfactory printing quality in using a normal paper, however, can be achieved only if the Beck smoothness of the normal paper is several ten or more seconds. The heat meltable ink can not be contacted with a concavity of paper, and the ink can not be transferred sufficiently to the concavity due to the low smoothness of the paper as shown in FIG. 2 to thereby cause blurring and leaving out of printing. To solve the above-mentioned disadvantages, reduction of the ink melting viscosity or the penetration of the ink from a convexity contacted with the ink into the concavity not contacted with the ink, have been proposed and developed. Outlines of the transferred ink print, however, are blurred and blotted, because undesired flowing of the ink results in certain printed areas where the ink should not have been transferred.
Furthermore, during thermal transfer printing correction of an erroneously printed character, since the ink penetrates into the paper, only a method for covering up over the incorrect character by whiting (cover-wrap method) has been proposed, thus resulting in poor outward appearance.